A THERMOCHEMICAL STUDY OF 2,2'-BIS(DI-P-TOLUENEPHOSPHINO)-1,1'-BINAPHTHYL

A thermochemical study of 2,2'-bis(di-p-toluenephosphino)-1, 1'-binaph thyl(Tol-p-BINAP) has been performed using adiabatic calorimetry, diff erential scanning calorimetry (DSC) and thermogravimetric analysis (TG ). The low-temperature heat capacity of Tol-p-BINAP was determined pre cisely with a small sample automated adiabatic calorimeter in the temp erature range from 80 to 350 K. No indication of any phase transition or thermal anomaly was observed in this temperature region. The high-t emperature heat capacity of Tol-p-BINAP was measured with a differenti al scanning calorimeter in the temperature range from 310 to 660 K. Fr om the DSC curve obtained for this compound, a solid-liquid transition was found at 528.29 K and the enthalpy and entropy of transition were evaluated as 41.98 kJ mol(-1) and 79.47 JK(-1) mol(-1), respectively. The TG analysis of Tol-p-BINAP was carried out in the temperature ran ge from 300 to 850 K, from which it was found that this compound start s to decompose at 662.13 K and transforms completely to naphthalene at 716.22 K in a single step. (C) 1997 Elsevier Science B.V.